Class Trait Survey

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Editor: Thomas Riggs
Date: 2018
Publisher: Gale, part of Cengage Group
Document Type: Experiment activity
Length: 607 words
Content Level: (Level 3)

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Class Trait Survey

Overview/Purpose

Every human is unique. And yet, when scientists examine the genetic material that makes us who we are, they find that every human's DNA differs by only 0.1 percent! Some of these differences are inherited traits passed down from parents and ancestors through genes.

Different forms of the same gene are called alleles. Some are dominant, and some are recessive. When a dominant and Page 292  |  Top of Articlea recessive allele are present, only the dominant allele is expressed. Polydactyly, or having extra fingers or toes, is a dominant allele. Someone who has the alleles for six fingers on each hand (dominant) and five fingers on each hand (recessive) will have six fingers on each hand. People who have five fingers on each hand do not have the dominant allele; they have only the recessive alleles.

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Think About It!

Some traits are a mixture of inherited and acquired traits. For example, top long-distance runners are usually tall with long arms and legs, an inherited trait. They are also lean, which is both an inherited trait and an acquired trait. Leanness can be inherited from our parents, but it is also affected by how we exercise and what we eat. Longdistance runners also need to know how to navigate difficult terrain without getting injured, which is an acquired trait. What other traits are a mixture of inherited and acquired traits?

While many of our traits are genetic, other traits are acquired. We get them from our experience rather than from our genetic code. For example, the ability to play a musical instrument is an acquired trait. Acquired traits cannot be passed down to offspring through genetic code, though some may be passed down through education or learned behaviors.


Trait Frequency in Humans Trait Frequency in Humans © 2018 CENGAGE®. © 2018 CENGAGE®.

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You will work in a three- or fourperson team to examine select inherited and acquired traits of yourself and your fellow team members.

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Troubleshooting

When examining traits, remember that scientists do not view particular traits as good or bad. For example, dominant traits are not better than recessive traits, or vice versa. Rather, scientists view genetic diversity as useful. After all, if we were all identical, we would have never evolved as a species! When examining your own traits and the traits of your group members, be respectful of differences. Traits tell the unique story of where we grew up and who are families are.

Suggested Materials

  • Pens or markers
  • Graph paper
  • Calculator
  • Pocket mirror

Approximate Budget

Free

Timetable

0–1 day

The Challenge

Your challenge is to gather information about specific inherited and acquired traits of all members of your group, including yourself. You will record your findings on the Genetic Trait Recording Sheet (located in the Appendix) and calculate the frequency of each trait.


Left-handedness is a recessive trait. Left-handedness is a recessive trait. © DIARMID COURREGES/GETTY IMAGES. © DIARMID COURREGES/GETTY IMAGES.

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WORDS TO KNOW
Acquired trait:
A characteristic that cannot be passed down through genetic material but is instead learned or otherwise acquired from the environment.
Allele:
An alternative form of a gene.
DNA:
The material in a living thing that determines what it will look like and how it will grow and function.
Dominant allele:
An allele that suppresses the expression of a recessive allele.
Gene:
A sequence of DNA found on a chromosome that controls inherited traits.
Inherited trait:
A characteristic that is passed down from parents to children through genetic material.
Recessive allele:
An allele that is expressed only when a dominant allele is not present.


Help Guide: How to Calculate the Frequency of a Trait Help Guide: How to Calculate the Frequency of a Trait © 2018 CENGAGE®. © 2018 CENGAGE®.

  1. Look at the list of traits on the Genetic Trait Recording Sheet. Take turns examining your team members, or use a mirror to examine yourself, for evidence of each trait. Record data for each group member.
  2. Calculate the frequency of each trait. The formula for calculating frequency can be found in the Help Guide below.
  3. Use a calculator to check your calculations.Page 295  |  Top of Article
  4. Using graph paper, make a bar graph of the data. Label the x-axis “Genetic Traits” and the y-axis “Trait Frequency (% Students).” For each trait, create two different- colored bars: one for dominant alleles and one for recessive alleles.
  5. Determine which alleles were the most common in your group and which were the least common. Then identify any traits that were highly skewed—that is, any that showed a large difference between the frequencies for dominant and recessive alleles.
  6. Write a brief paragraph summarizing your findings.
  7. Proofread your paragraph and correct any spelling and grammar errors.

Evaluation

The success of your survey results will depend on the care with which you observed and recorded your information, as well as the accuracy of your calculations. Your paragraph should demonstrate your understanding of the survey results and should be free of errors.

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WANT TO KNOW MORE?

For more about how scientists breed plants and animals with specific traits, visit https://www.nature.com/scitable/topicpage/inheritanceof-traits-by-offspring-followspredictable-6524925 .

Extension

Now that you have surveyed your classroom, give the survey to your family to see how your traits compare to those of your family members. You might also survey your extended family to see how traits are distributed through your family tree.

Source Citation

Source Citation   

Gale Document Number: GALE|CX3679900069